title: Microfilters for biomedicine obtained by swift ion processing.
abstract: Swift ions with 50 MeV energy are used to irradiate bio-polymeric films. Lithium, carbon and oxygen beams, with fluencies ranging between 10(8) and 10(13) ions/cm2, are swept on large surfaces of hydrogenated and fluorated polymers. The electronic stopping power of the ion induces high rates of ionization, excitation and radical formation along the ion path with production of chain-scission and cross-linking processes which can be investigated by the molecular emission from the irradiated polymer. The radiation damage increases the chemical solubility of the material around the ion track up to distances of the order of 100 nm. A suitable chemical etching removes the damaged material leaving micrometric holes in the polymeric film. This process gives rise to micro-perforated films which can be used as microfilters, with sub-micrometric pore dimension, high selectivity and controllable porosity. Their use is very interesting for special applications in ultra- and microfiltration of biological liquids.
authors.affiliation: Dipartimento di Fisica di Messina, Università di Messina, Italy. Torrisi@alpme2.me.infn.it
authors.forename: L
authors.initials: L
authors.lastname: Torrisi
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000528:radiation effects; D001698:Biomedical Engineering / Q000379:methods; D002244:Carbon / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D004583:Electrons; D004867:Equipment Design; D005609:Free Radicals / Q000737:chemistry; D007477:Ions; D008094:Lithium / Q000737:chemistry; D008567:Membranes, Artificial; D008851:Micropore Filters; D008855:Microscopy, Electron, Scanning; D010100:Oxygen / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry* / Q000528:radiation effects; D011138:Polytetrafluoroethylene / Q000737:chemistry* / Q000528:radiation effects; D011145:Polyvinyls / Q000737:chemistry* / Q000528:radiation effects; D016062:Porosity; D011829:Radiation Dosage; D011839:Radiation, Ionizing; D012995:Solubility; D013499:Surface Properties; D013679:Technology, Radiologic / Q000379:methods*; D014462:Ultrafiltration / Q000295:instrumentation; D005465:Fluorocarbon Polymers
chemical_list: D001672:Biocompatible Materials; D002244:Carbon; D003432:Cross-Linking Reagents; D005609:Free Radicals; D007477:Ions; D008094:Lithium; D008567:Membranes, Artificial; D010100:Oxygen; D011095:Polyethylenes; D011138:Polytetrafluoroethylene; D011145:Polyvinyls; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers